Two ponds along the north side of State Route 299 are closed to the public while Whiskeytown National Recreation Area awaits test results for possible cyanobacteria.

One of the ponds is along Grizzly Gulch, and the other is referred to as Second Pond, according to a press release issued Friday by the park. Caution signs have been posted to alert the public that the blooms may be present and these bodies of water should be avoided.

The discoloring of these ponds may be due to a variety of causes, such as stagnant water, increased water temperatures, increased nitrogen inputs from the Carr Fire and naturally occurring minerals and salts from the upstream creek.

Blue green algae can appear reddish purple, brown, blue-green and cause the water to look murky. Most species are buoyant and will float to the surface where they form scum layers or floating mats.

Do not let pets go into these areas or allow them to drink the water. Be sure to rinse pets off if exposed. Visitors should swim in areas with good water circulation, and are encouraged to check the park’s Facebook page for updates.

To learn more about Whiskeytown, visit the www.nps.gov/whis or stop by the Visitor Center 10 a.m. to 4 p.m. seven days a week.